Ground probes

[Staceon]

Can anyone answer my question?

[horge]

Staceon:
I don't know if your 6-gang power strip has ground-prong slots. And if it did, if those would be honestly wired on through the powerstrip's own ground prong?

For my money, I'd personally skip the house electrical system altogether and run a wire from the probe outside to a grounding spike (errr, spiked into the ground )

If I've misspoken, somebody correct me quick, hehe. But as MLP pointed out earlier, you can't really be sure (short of testing) that the grounding prong socket(or even the faceplate frame for the grounding screw) of a given power outlet is actually GROUNDED.

[This message has been edited by horge (edited 03-14-2000).]

[Staceon]

Yes the powerstrip has a ground prong slots and the strip itself plugs into the wall with a ground on it.

[turbo]

If AC voltage is on & off, please explain the bottom half of the sin wave. It is not just measuerd in Hz. It's also measured in volts. Time to do some research, I'll be back.

Thanks

Paul

[This message has been edited by turbo (edited 03-14-2000).]

[This message has been edited by turbo (edited 03-14-2000).]

[turbo]

I pulled this from the Britannica website, here's the url.
http://www.britannica.com/bcom/eb/ar...8498+7,00.html

ENCYCLOPÃâ€*DIA BRITANNICA


electricity

Alternating electric currents

Basic phenomena and principles

"Many applications of electricity and magnetism involve voltages that vary in time. Electric power transmitted over large distances from generating plants to users involves voltages that vary sinusoidally in time, at a frequency of 60 hertz (Hz) in the United States and Canada and 50 hertz in Europe. (One hertz equals one cycle per
second.) This means that in the United States, for example, the current alternates its direction in the electric conducting wires so that each second it flows 60 times in one direction and 60 times in the opposite direction."

This was another URL I found: http://www.landfield.com/faqs/electr...ection-23.html

"A GFCI is a ``ground-fault circuit interrupter''. It measures the current flowing through the hot wire and the neutral wire. If they differ by more than a few milliamps, the presumption is that current is leaking to ground via some other path. This may be because of a short circuit to the chassis of an appliance, or to the ground lead, or through a person. Any of these situations is hazardous, so the GFCI trips, breaking the circuit.

GFCIs do not protect against all kinds of electric shocks. If, for example, you simultaneously touched the hot and neutral leads of a circuit, and no part of you was grounded, a GFCI wouldn't help. All of the current that passed from the hot lead into you would return via the neutral lead, keeping the GFCI happy.

The two pairs of connections on a GFCI outlet are not symmetric. One is labeled LOAD; the other, LINE. The incoming power feed *must* be connected to the LINE side, or the outlet will not be protected. The LOAD side can be used to protect all devices downstream from it. Thus, a whole string of outlets can be covered by a single GFCI outlet."

Can we please put this issue to bed now.

Thanks

Paul

[This message has been edited by turbo (edited 03-14-2000).]

[This message has been edited by turbo (edited 03-14-2000).]

[badgers]

A ground probe will help the GFI function.


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I'm so skeptical, I can hardly believe it!
The facts, although interesting, are irrelevant

[MLP]

turbo,
Man this is a hard way to have a conversation! Ok, We have chosen some poor words and picked some poor ways to get across our thoughts. Sheesh, what a can of worms I opened!

Let me say that I have never used and do not plan on using a GFCI anytime soon for my tanks. Kitchens & bathrooms, yes because code requires it.

Again, my statement that started all of this was as I had be told be an electrical contractor (several years ago) also I red it a couple of years ago in an article:

quote:

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Some hobbyists with engineering knowledge have correctly pointed out that grounding the aquarium may create a hazard for the aquarist, irrespective of any beneficial effect on the tank’s inhabitants. The wire leading from the water to a ground on a nearby electrical circuit provides a path for current to flow in the event of an accident, such as a heater breaking or a light fixture falling into the water.

Further, the ability of a ground fault circuit interrupter (GFCI) circuit breaker to interrupt the power flow in such an accident situation is thwarted by grounding the tank. Either problem is clearly a good reason not to ground the tank or to make absolutely certain all power sources are disconnected before putting one’s hand into the water.

---

Like I said, it seemed to make sense to me. Furthermore, since I do not use a GFCI around my tanks I did not pursue it any further. All of this and my recent research makes me question that, at least a bit. A simple test would answer that question though!

OK on to some of the confusion. You said;

quote:

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The GFCI wants to see 120v on the hot & 120v on the neutral, if it doesn't see that it will trip.

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I still disagree with this as it is written. In home AC wiring the black (line) wire carries voltage and that is it. The white (neutral) wire (sometimes called return) is just that, "Neutral" it carries no voltage, so to speak, it completes the circuit. In a home with a grounding rod driven into the ground, the neutral and the ground from the grounding rod are connected together inside the breaker box. I know this for a fact as I just did it on Dec 15 when my meter box burned out. Per electrical code and the scrutinizing inspections of the city inspector, to meet code on the new 200amp service feed I had to drive a ground rod (this is a very old house) and run it to my breaker box, tie it into the common (neutral) bar there and also run it up into the meter box and tie it directly into the common line that ties to the city power feed lines from the pole. Yes I did this, I did not pay someone else to do it, so I know exactly what and how it was done.
So my point is, is that there is no 120volts in the neutral line for the GFCI to compare to.

As for AC Voltage. It gets to me every time that someone says "it goes both way" That and I figured you were using this to substantiate the fact that there was voltage coming back from the neutral wire, made me grab at something real quick on the way out the door to get you to do some thinking and hopefully digging. And it did.

AC voltage alternates, its charge from positive to negative 60 time a second here in the US, ie: 60 cycles or 60 hertz. However, the actual flow of the electricity that does what we need it to do is in one direction. It enters our house via Line (black wire) and flows through our load (light, motor or whatever) where the voltage is used and the circuit current (not voltage) flows out the neutral wire.

Now (after digging into it) I understand the basic principle that the GFCI works on. It compares current (not voltage) on the line and load sides. What needs to be understood here (and this is why I disputed most of what you have said) is that voltage drops at the load source. So, 120volt into a light bulb, the light bulb burns and, zero voltage out. (well actually it is < 0.5 volts if I remember correctly) in other words all the voltage is used. However, Current stays the same throughout the circuit. Before, at and after the load current is the same for the given circuit. The GFCI compares the current before and after the load and looks for a variance. If that current variance is more than 5mA, then it trips. That makes me Q what I have been told and read about GFCI's and grounding probes in tanks, but I will still investigate that further.

Now on a couple side notes. hehehehehe

You said:

quote:

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Due to the natural high resistance of the human body, it's going to take some amps to push that voltage through.

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Actually the human body has very low resistance and it a very good conductor.

Take a look at ohms law:

E = I x R

E --- volts
I --- current in amperes
R --- resistance in ohms

To find voltage: E = IR
To find amperage: I = E/R
To find ohms: R = E/I

If voltage remains constant, the current flow goes down if the resistance goes up.

That is why insulators and non-conductors do not flow electricity, they have high resistance. However, we have very low resistance, that is why we can get electrocuted so easily. If we had high resistance, electricity would not flow through our body. We are very good conductors, all things considered. Also, remember, Current (amperage) is what hurts us, not voltage. Ever been shocked by a spark plug wire on a car?? The old ones had at least 30,000 volts in them, the new ones are up to 80,000 volts, but there is no amperage.

BTW, in your quote of the GFCI page you omitted a word. I;m sure thinking it was a typo on their part. In all actuality that word you omitted is very important and when I read the actual page It made sense and went back and re-read your quote of it and noticed that you omitted a word that helped me understand the whole thing.

You quoted:

quote:

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"A GFCI is a ``ground-fault circuit interrupter''. It measures the current flowing through the hot wire and the neutral wire.

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The actual page said:

quote:

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A GFCI is a ``ground-fault circuit interrupter''. It measures the current current flowing through the hot wire and the neutral wire.

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It doesn't just measure current, but monitors and measures current at that particular moment. ie current current.

Here is one of the reasons I do not use a GFCI on my tanks:

quote:

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Subject: Where shouldn't I use a GFCI?

GFCIs are generally not used on circuits that (a) don't pose a
safety risk, and (b) are used to power equipment that must run
unattended for long periods of time. Refrigerators, freezers,
and sump pumps are good examples. The rationale is that GFCIs
are sometimes prone to nuisance trips. Some people claim that
the inductive delay in motor windings can cause a momentary
current imbalance, tripping the GFCI.

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Happy Reefing,
Michael
Aquaria Central

Learn from the mistakes of others, Life is too short to make them all for yourself!
An ounce of prevention is worth a pound of cures.

[Canadian]

No offense MLP, but Badgers has proven to know his sh*t. His simple statement, "A ground probe will help the GFI function." is enough for me. If you want an explanation regarding this just ask Badgers. If he has time I'm sure he'll thoroughly explain everything.

Andrew

[turbo]

I'm sorry, I guess The Encyclopedia Britannica is wrong, I guess the Electrical Engineers who design GFCI's are wrong and lastly I'm wrong.
BTW, I've been a Master Technician for the past 20+ yrs and I deal with AC, DC, Ohm's law and most important, Common Sense issues everyday. I am not going to waste any more time on this. I am now going to bow out gracefully.

Thanks

Paul

[MLP]

Canadian
I don't remember having a conversation with you anywhere in this thread! I was responding to the discussion I was having with turbo.

turbo

quote:

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I'm sorry, I guess The Encyclopedia Britannica is wrong, I guess the Electrical Engineers who design GFCI's are wrong and lastly I'm wrong.

---

Excuse me?? In what is that reference to???

BTW, I have been a Master Technician for the past 25+ years, and considered to be one of the best diagnostic techs in my area! So what's your point?
If you are going to get offended in a discussion don't partake in it. Seems in my last post I agreed (twice even) that my findings on researching how GFCIs work contradict what I have been told and read in the past on this. I see no reason for your last snipe at me. Oh well I'm not going to loose any sleep over it.

Cheers,
Michael

[horge]

Paul and Michael, if you felt offended by each other's quoting from books, understand that neither of you had an idea you were both EMTs who would feel being talked down to. This needn't be a waste. You've both made me realize that there's an awful lot I ought to know about for my own practice. I highly suspect future interaction, comparison and exchange would help others.

Canadian, I've enjoyed your past input a lot, and your last post on this thread surprised me. I would go slow using that tone on even the most inexperienced member of the board.

I'd go even slower using it on one of this board's founders.

[Larry M]

Too bad an actual electrician doesn't jump in here. One thing I've learned over the years is that knowledge gained in one field doesn't necessarily transfer to a similar one. As I mentioned earlier, I'm no electrician but I see what appear to be inaccurate statements on both sides. Any master electricians out there who care to get involved in this?
Horge, MLP has always been a friend but he is not a founder of this board. I think you might be referring to MIKE, a different cat altogether.


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Larry M

See my tanks at Northern Reef

[bmw]

I agree Larry.
As indicated earlier, I asked some professionals in this field. They advised me to get a gfi breaker, put a ground probe in it. Thought that was the final word.
Now--I dunno. Here are two people, seem to both be knowlegable, arguing over the facts.
Then I see Levetron puts some erronous info in one of their own gfi boxes, which upon calling them, they scratch their heads, and admit is wrong--not sure why it was put in.

I'll admit--I am a little spooked at this point. Besides my own life, I got two small kids-who shouldn't have access to tank or sump-but knowing kids they might find a way.

I can live with fish getting zapped, power being cut off falsely. But my own and my children's safety is something that cannot be compromised. With all due respect, I think this is about as serious subject that can be discussed on this board. I hope egos, frustrations with communications, etc. can be put aside for awhile.
Please help give the facts-whoever you might be.
Thank you,
Bruce

[Larry M]

Very well said, Bruce.

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Larry M

See my tanks at Northern Reef

[badgers]

The following quotes have had the posters name removed. I did this because I don’t want this directed at anyone. Electricity can’t be seen and that makes it difficult to get a gut feel for what is going on. It appears that some people are becoming uneasy regarding the safety of their tanks. This is written based on human safety, and not the safety or well being of the tank inhabitants, because I don’t know what is best for the tank critters.

[qoute]Note: In accordance with NEC Article 210-7(d), a GFCI receptacle may be used to replace an existing non-grounding 2-wire receptacle. In addition, existing non-grounding 2-wire receptacles may be replaced with grounding-type receptacles when they are supplied through a GFCI receptacle. (In this case, however, a grounding conductor should not be connected between the GFCI receptacle and those receptacles that it supplies).
I found it interesting that a GFCI receptacle may be used to replace an existing non-grounding 2-wire receptacle. I hadn't thought about it but it makes sense. Since as I mentioned above, the GFCI looks for the surge (that may be a bad word to use, but you should know what I mean) internally. So it does not require a ground connected to itself to trip. In this case it would not provide any ground protection, just power interrupt[/quote]
This is a good example of how a GFI can not be looking at the voltages present. The GFI is looking for a current imbalance. A GFI is a zero sequence detector, it doesn’t care where the current leak is(a person, ground probe, capacitive coupling in wires or a ballast). this is why the GFI does not need the ground wire. If it was checking the voltage it would need the ground wire to measure it.
If the current on the hot and neutral are not equal by +/- 5ma then the device trips. A ground probe will help a GFI function by giving electrical energy a different/low impedance path back to the electrical panel in the event of an exposed wire. The GFI guards against the wires becoming exposed to the water. This is different then an induced voltage in the tank from an electric or magnetic field.
I agree that some GFI’s are more reliable then others but I don’t know that it is that big of a deal for our applications.
The ground to neutral bond can also be troublesome for some homes. Peoples experiences with voltage on a ground wire in their home is a common problem. Farmers have noticed this regarding their livestock. Because the transformer feeding a house is typically very far away the problem can become more sever. Connecting a ground probe to an isolated ground rod will not help a gfi function, but this isolated ground rod will be less electrically noisy then one connected to your panels ground bar.
Your home ground system has a voltage impressed on it equal to the voltage drop of your neutral wire from the utility transformer to your electrical panel. Years ago it was customary to reduce the neutral size, so older homes may experience more voltage drop on the neutral then a newer home. This also explains how seemingly unrelated equipment can cause electrical noise in other pieces of equipment. You may here stories of how a person added a ground probe and when they put their hand in the tank they could feel a tingle. These homes most likely had a high voltage drop on the neutral wire.
In response to the original question, I don’t know. I am not a biologist so I don’t know how it affects livestock. I bought one and I do not have it installed. I have just put it off because I am lazy and been dealing with trying to catch some crabs in my live rock. Any suggestions will be appreciated If I do put it in it will go in my sump which is where all my “stuff� is. I would put it in more for the operation of the GFI then for the livestock.
The following is just my speculation and is not based on any test results or documented studies.
assuming that an entire volume of water is at the same voltage is a mistake in my opinion.
It is true that to have current flow you need a difference in potential. An induced electrical field or a magnetic field falls off at the square of the distance. A source of an electrical field will create a gradient around it. If one heater could raise the entire tank to the same potential it would blow my mind. Something has to limit the dispersion of an electrical field or it would go on forever.
There is a limited amount of energy being emitted, it can not be infinite.. By shunting that energy to ground in the form of more current you then limit the voltage. I would place the ground probe as close to the heaters and pumps as possible. This would cause the field to drop off very quickly keeping it from the tank. I would be cautious of some “studies� which used electrical meters to test the tank voltage. There are two leads on a meter, one in the tank and one some where else. Where you put that second lead is critical because it is your reference. Put a ground probe in your tank and then place one meter probe in the water and the other on the ground prong of your receptacle and you will read very near 0 volts. Congratulations you just measured the voltage at two ends of the ground probe. The ground probe and the meter share the ground connection in the receptacle and share the connection in the tank. If your ground has 8 volts on it your meter will not see it. Connecting a meter from the tank to an isolated ground rod will give you a different perspective on things. Which is correct? I don’t know. We drive by and live by sources of electrical and magnetic fields every day. Radio stations broadcast towers, cell towers, etc.
Because the electrical and magnetic fields can not go on for ever I think that placing things in the sump would help in any case. The farther potential sources of electrical and magnetic fields are from the live stock the less intense these fields will be in the main tank.
Bottom line, biology is far more complex then simple electrical engineering. I got the ground probe for 11 bucks. If I add the probe and the live stock responds poorly then I will get rid of the probe. If I add the probe and nothing happens then I will keep it to help the GFI and breaker trip. If I add the probe and the fish respond better then I will definitely keep the thing. I don’t care how good your argument is, if the fish freak then the probe goes out the window. I really believe that each case will be unique depending on the “quality� of the home/building grounding. Do not assume that the ground or neutral are at zero volts. They are most likely very low and I would say that 10 volts would be high. But I think that 2 volts would be common.
Back to some facts
For those who were/are worried about this. From a safety standpoint you want everything grounded except you. The NEC requires many things to be grounded because it increases safety for people. Every metal conduit and water pipe is required to be grounded by the NEC. For swimming pools and spas the metal ladder used for getting in and out of the pool is requried by the NEC to be grounded(big ground probe). Any conductive surface withing 6 feet of a pool/hot tub must be grounded. The pool and spa pumps are required to be GFI protected. Ground probes in the sump/tank will increase safety there as well. The GFI will also increase safety for a person.
“I can live with fish getting zapped, power being cut off falsely.�
This is the only possible down side to adding a ground probe and a GFI.
thank you for your time and have a good day


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I'm so skeptical, I can hardly believe it!
The facts, although interesting, are irrelevant

[bmw]

Well!

I guess that college prof did know a thing or two. I feel better.

Thank you sir.
b.

[hesaias]

You go badgers!
You too BMW, cool smilies!
Lar can we get the ones BMW used? Huh? Puleeezzzz!??!?!
BTW, amps= flow
volts, watts= the part that makes stuff work
flow goes from hot, to the appliance, pump, etc, volts and watts make it work, flow returns via neutral side. A GFI reads flow(Amps) If the amps on the hot side and the amps on the neutral side are not within + - 5ma, it trips. Therefore if the watts and volts goes to somewhere it needs amps to take it, the amps dont equal out and it trips(ie. you, the tank, your cat, etc ) If the power goes to ground, same thing. If you dont have a GFI, you then must rely on your breaker. 1 amp is more than enough to kill a person. My smallest breaker is 15 amps. If a GFI trips at 5 milliamps, you live to reef another day.
All this is just a simpler explanation(and I hope its right , badgers, correct me if Im wrong) for lay reefers like myself, badgers has the technical stuff down pat

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hesaias

My Homepage

[horge]

Oh yes.
It will take me a day at least to sift through everything posted FWIW I use both GFI's and crude gprobes --I now can try to understand how it works. Thanks everyone.

Sorry, MLP, for confusing you with someone else.
MIKE, wherever you are, my apologies too.
Canadian, I just thought you were having a bad day My apologies if I offended you by pointing it out.

Larry, my apologi ----hey... the way I figure it, you OWE me for posting dumb CAT PICTURES (brrrr) in the Lounge!

[Canadian]

Horge, MLP and anyone else I may have offended with my post- Yes I did indeed have a bad day yesterday and brought it to the board with me; I appologize.

I am however glad that Badgers decided to post here and straighten things out a bit.

Andrew

[turbo]

Larry, Horge, Bmw,
You guys are right. I apologize for getting a little miffed and ruffling my feathers. The last thing I wanted to happen was to start a flame war. I come to this board to avoid that. Maybe I mis-read MLP's last post, because I really didn't see an agreement to the ground probe issue (also explained by Badgers/engineer), the AC both direction issue (as defined by Britannaca), or the GFCI issue, seeing that he does not plan using one in the first place and was offering incorrect advice on it. MLP, if I did mis-read your post I apologize for that also.

Thanks again

Paul